Housing for a gas or steam turbine



Fell 14, 1967 K. oEcHsLlN ET AL HOUSING FOR A GAS OR STEAM TURBINE FiledDeo. 27, 1965 United States Patent O land Filed Dec. 27, 1965, Ser. No.516,538 Claims priority, application Switzerland, llan. 12, 1965, 372/6516 Claims. (Cl. 253-39) This invention relates to a housing for a -gasor steam turbine, having an outer housing and an inner housing, fthelatter comprising a stationary guide apparatus, a partition separatin-gthe intermediate space between inner and outer housing into aninlet-side intermediate space and an outlet-side intermedaite space, anda supporting eletment for the inner housing.

Housings of this kind, as is known, are used more particularly when theworking medium under pressure has high temperatures. The inner housingthen serves for guiding the flow of working medium and as Sup-port forthe guide 'blades of the turbine, and the intermediate space between thehousings contains a heat insulating material, the inner housing takingup substantially the inner temperature, and the outer housing the innerpressure.

The connection between the outer housing and that part part of the innerhousing which receives the guide blades must take up the temperature`gradient occurring between the housings, as well as the forces actingaxially on the `guide blades in the direction of the outlet-side, and atthe same time, keep the lguide -blades as far as possible in the sameposition in relation to the moving blades.

Flange holding means are known, lin which the flange is provided on theoutlet-side end of the inner housing portion receiving the guide blades,and at the same time forms the partition between the inlet-sideintermediate space and the outlet-side intermediate space between thehousings. This embodiment, apart from the advantage of the axiallycompact construction, has considerable disadvantages. The rotor shaft is`advantageously mounted on the inlet-side axially outside the turbinehousing, and if necessary is cooled from that side up to the firstguideblade ring exclusive.

In operation, the rotor is heated substantially from the firstmoving-'blade ring onward, and expands axially from that place in thedirection towards the outlet-side of the turbine. The inner housingportion, receiving .the guide blades and heated in like manner inoperation is, on the contrary, xed by its outlet-side end to the holdingange, and is fixed by means of the latter relatively to the outerhousing, and the inner housing portion receiving .the guide bladestherefore expands axially -towards the inlet-side. The effect of this isthat the moving-blade apparatus and the guide-blade apparatus expand inopposite directions and correspondingly produce a considerable axialdisplacement of the moving blades and guide blades in relation to eachother, which results in a danger of stripping, inadmissibly increasesthe radial play at the outer, conical -moving blades and interferes withthe accommodation of a sufficient number of labyrinth joints between-guide wheels and rotor. Another important disadvantage lies in theconsiderable accumulation of material in the holding flange, which hasto take up a considerable temperature gradient, resulting in a risk ofthe inner housing becoming non-circular in its region receiving theguide blades.

It has been proposed to arrange, coaxially with the inner housingportion receiving the guide blades, as supporting element, a thinfrusto-conical shell, provided with holes and consisting of material oflow thermal conductivity, the wider end of which conical shell is fixedto the partition and its narrower end to the inlet-side end of the innerhousing portion receiving the .guide blades, the inner housing 'beingaxially displacea-ble in relation to the partition. This embodimentobviates displacement of the moving and guide blades in relation to eachother, but the inner housing portion receiving the guide blades issubjected to tension, so that it is only possible to use an innerhousing construction which is capable of taking up tensile forces.

It is the object of the invention to overcome the hereinbefore describeddrawbacks. For this purpose, a turbine housing of the kin-d hereinbeforedescribed is developed, according to the invention, in that theinlet-side narrower end of the truste-conical shell carries theinletside end of a substantially cylindrical supporting ring, whichsurrounds the inner housing at least over part of the portion of thelatter receiving the guide blades, and the outlet-side end of whichcarries the inner housing, the frusto-conical shell in the manner knownper se, and/or the supporting ring having openings in the part thereofsituated in the linlet-side intermediate space.

A constructional example of the subject of the invention is shown insimplified form in the drawing, in which:

FIG. l shows an axial section through a housing of a gas turbine, and

FIG. 2 shows a portion of a section at right angles to the axis on theline II--ll in FIG. 1.

The turbine housing has an outer housing 1 and an inner housing, whichon the inlet side comprises the inlet part 2 and the port-ion 4receiving the guide blades 3. 5 denotes t-he rotor carrying the discs 6with the moving blades 7. Both the inlet-side part 8 and the outlet-sidepart 9 of the intermediate space between the housings is filled withheat insulating material 10. An axially fast, two-part ring 12, centredin the outer housing 1 by tour cotters 11 and four lugs 13, each securedto a block 14, connected to the ring 12 by screws, not shown, whic-hlugs by means of four cotters 15 centre a two-part ring 16 belonging tothe axial portion 4 of the inner housing, form together with a sealingrin-g 17 of known construction a partition between the inlet-side part 8an-d the outlet-side part 9 of the intermediate space between thehousings, the ring 16 being axially displaceable relatively to thepartition 12, 13, 17.

The sealing ring 17, in known manner, consists of an outer ring 18,mounted axially fast in a sealing manner in the outer housing 1, and aninner ring 19, co-axial with said ring 18 and secured to the outlet-sideend of ring 16, the co-axial play provided between rings 18, 19 beingbridge-d by a thin, one-part diaphragm 20.

A two part frusto-conical shell 21 is secured as supporting element byits wider orifice to the ring 12. This frusto-conical shell 21 has athin wall thickness and consists of austenitic material of low thermalconductivity.

The rotor 5 is mounted axially outside the turbine, not shown in thedrawing, in an air compressor, assembled with it. A gap 22, recessedbetween the rotor shaft and a tubular part of the outer housing 1 allowscool working medium from the air compressor to flow along the rotorshaft to the first guide-blade ring. The inlet part 2 of the innerhousing is centred radially and axially movable in the cold compressorhousing 24 by means of four cotters 23, and the inner housing portion 4receiving the guide blades 3 is centred radially and axially movable inthe region of its inlet-side end by means of four cotters 25.

The truste-conical shell 21, at its narrow inlet-side end, has a iiange26 and by means thereof carries the inlet-side end of a two-partcylindrical supporting ring 27, the latter being connected to the flange26 by screws 28. The outlet-side end of the supporting ring 27 isconnected to the ring 16, which is situated on the outlet-side of thelast guide blade ring and surrounds the last moving blade ring. Of thetotal of iive guide-blade rings and tive moving-blade rings, thesupporting ring 27 together with the ring 16 surrounds the threeoutermost guide and movingblade rings situated downstream. Thesupporting ring 27 has longitudinal slots 29, the Wall parts between thelongitudinal slots in the peripheral direction being a multiple of thewall thickness, and the space bounded by the frusto-conical shell 21,the supporting ring 27 and the sealing ring 17 being also lilled withheat insulating material 10.

During operation of the turbine, the rotor with the discs 6 and themoving blades 7 ixed to the latter is heated by the hot working mediumand expands axially in the direction towards the outlet-side of theturbine. The inner-housing portion 4 receiving the guide blades 3 isalso heated mostly by the working medium flowing through the guideblades and moving blades, and to a lesser extent by the heat passingthrough the inlet par-t 2 of the inner housing through the insulatingmaterial 10. The supporting ring 27 is heated mostly by the ring 16, andto a lesser extent by the heat passing from the inner housing throughthe' insulating material 10, so that it has approximately the sametemperature as the inner-housing portion 4 receiving the guide blades.The maximum temperature, namely that of the supporting ring 27, isimparted to the frustoconical shell 21 at its line of contact with theiiange 26, while its lowest temperature, substantially corresponding tothe temperature of the outer housing 1, lies on its line of contact withthe ring 12. The effect of this is that the axial expansion of thefrusto-conical shell 21 remains within insignificant limits, like thatof the known embodiment, and that the region of the ange 26 is displacedby an insigniticant amount only, in the direction towards the inlet-sideof the turbine. Since, inthe region of the innerhousing portion `4receiving the guide blades, this portion 4 as Well as the supportingring 27 are heated essentially approximately equally, and :all theseparts consist of material having the same thermal expansion, the guideblades 3 and moving blades 7 of the turbine remain inapproximately thesame axial position relatively to each other Within theV entire workingrange. Thevthermal expansion of the frusto-conical shell 21 may bereduced additionally in manner known per se by means of holes therein,and the thermal expansion of the supporting ring 27 may be increased byomitting insulating material between supporting ring and inner housing,and in this Way, minimum relative displacement between guide-bladeapparatus and moving-blade apparatus is effected.

Different radial thermal expansions of the inlet-side and outlet-sideends of the supporting ring 27, due to different temperatures in theseregions, do not load the supporting ring inadmissibly, on account of thelongitudinal slots 29 in the latter.

The axial thrust acting on the guide blades 3, or on the inner-housingportion 4 receiving said blades, during the operation of the turbine, inthe direction towards the outlet-side is transmitted by the ring 16 tothe supporting ring 27, by the latter to the frusto-conical shell 21 andby the latter to the outer housing 1. Due to the step according to theinvention of the use of a supporting ring, the innerhousing portionlreceiving the guide blades is subjected exclusively to compressionstresses.

The guide blades 3 are mounted in tive two-part guideblade rings 30, thecorresponding halves being connected together by screws 31. Between eachpair of adjacent guide-blade rings, there is arranged one of a total offour one-part intermediate rings 32. Each of these four intermediaterings 32 surrounds a moving-blade ring 6, 7, and the outlet-side lastmoving-blade ring of the total of five such rings is surrounded by thering 16, which has an inner radial groove 33, in which 4an outer radialkey 34 of the outlet-side last guide-blade ring is held fast axially.The said outlet-side last guide-,blade ring is centred 4 radiallymovable in the ring 16 by means of four cotters 35', which cotters alsotransmit the torque of the innerhousing portion 4, carrying the guideblades, to the ring 16.

The intermediate rings y32 have on each end face an inner rim 35,whichengages with close t a corresponding recess 36 of the respectivelycontiguous guide-blade ring 30, whereby each guide-blade ring is centredrelatively to the intermediate ring immediately adjacent it. Eachguide-blade ring 304 has an outer peripheral groove 37. Eachintermediate ring 32 is connected to the two adjacent guide-blade rings30 by means of screwbolts 38 passing throughthe intermediate -ring 32and extending into the peripheral grooves 37 of the guide-blade rings30, the nuts of the screwbolts 38 lying in the peripheral grooves 37 ofthe guide-blade rings 30, The rings 30, 32, 30, connected together ineach case by a ring of such screwbolts, are connected togethernon-rotatably, by a ring of axial cotters 39, which extend over allthree rings and are accommodated in axially flush grooves 40.

Non-circularity of the individual guide-blade rings'30 on heating, dueto their two-part construction, and owing to the irregularity of thecross section of the material in the peripheral direction at the jointsof the two halves, necessarily associated with such construction, iskept within-negligibly small limits by the one-part intermediate rings32, or the mutual centring of the guide-blade rings relatively to theintermediate rings.

Due to the thrust of the individual guide-blade rings occurring inthedirection towards the outlet-side on operation of the turbine, theindividual rings 30, 32 are pressed against the rings which, seen fromthe position of the ring in question, are on the outlet-side of them,and the latter are pressed against the ring 16 supported axially in theouter housing 1 through the supporting rin-g 27 and the frusto-conicalshell 21, the screwbolts 38 having no important tensile forces to takeup.

From the hot ring 16, which is connected in a good heat-conductingmanner with the rings 30, 32, only a little heat iiows through the lugs13 and the diaphragm 20 to the cold outer housing 1, so that inl thisregion, no important thermal stresses are set up, which could produce adeformation.

The high stability of the inner-housing portion receiving the guideblades makes it possible to construct this portion of light weight andwith comparatively thin walls, whereby a considerable saving inheat-resistant material is eiected.

The development of the inner housing portion receiving the guide bladesaccording to the invention thus provides, with slight expenditure inmaterial, a very stable construction, which is subjected to littledeformation and remains circular to a considerable extent.

What is claimed is:

1. In an axial flow gas or steam turbine, an outer housing and an innerhousing, said housings confining an intermediate space; heat insulatingmaterial disposed in said intermediate space; a plurality of axiallyspaced circular series of inwardly extending guide blades arranged overan axial portion of said inner housing; said axial portion of said innerhousing and said guide blades thus forming a stationary-guide apparatus;a partition separating said intermediate space into an inlet-sideintermediate space and an outlet-side intermediate space; means forconnecting axially fast in a sealing manner and for centering saidpartition non-rotatably relatively to said outer housing; means forcentering and for connecting in a sealing manner said inner housing tosaid partition to be axially displaceable relatively to the latter; asupporting element for supporting said inner housing, having athin-walled frusto-conical shell consisting of material of low thermalconductivity, arranged in 4said inlet-side intermediate space, co-axialwith said inner housing, -its wider end facing said partition, and meansfor connecting axially fast and for centering non-rotatably said widerend lof said frusto-conical shell relatively to said outer housing, anda substantially cylindrical supporting ring, co-axial with said innerhousing and surrounding the latter at least over part of `said guideapparatus, the inlet-side end of said supporting ring being rigidlyconnected to the narrower end of said frusto-conical shell, and meansfor connecting axially fast and for centering non-rotatably theoutlet-side end of said supporting ring relatively to said innerhousing; and openings in the portion of the walls of said supportingelement lying Within said inlet-side intermediate space.

2. The combination defined in claim 1 in which the outlet-side end ofsaid supporting ring is connected With the outlet-side end of said guideapparatus.

3. The combination defined in claim 1 in which said partition isconnected with the outlet-side end of said guide apparatus.

4. The combination defined in claim 1 in which said supporting ring haslongitudinal slots.

5. The combination defined in claim 4 in which the Wall parts of saidsupporting ring between said longitudinal slots in the peripheraldirection amount to a multiple of the Wall thickness.

6. The combination defined in claim 1 in which said partition comprisesa ring; inwardly extending lugs fixed at said ring having at their innerends cotters for centering said inner housing; a sealing ring forbridging the openings left free by said lugs, said sealing ringcomprising an outer ring mounted axially fast in a sealing manner onsaid ring and an inner ring co-axial with said outer ring and mountedaxially fast in a sealing manner on said inner housing, and a thincorrugated one-part diaphragm bridging the co-axial play between saidrings of said sealing ring.

7. The combination described in claim 1 in which said means forconnecting axially fast in a sealing manner and for centeringnon-rotatably said partition relatively to said outer housing comprisean inner peripheral groove in said outer housing, the axially outerportion of said partition engaging with close axial fit in said groove,and cotters.

8. The combination defined in claim 1 in which said means for connectingaxially fast and for centering nonrotatably said wider end of said-frusto-conical shell relatively to said outer housing comprises a ringrigidly connected with said wider end of said frusta-conical shell, ainner peripheral groove in said outer housing, said ring engaging withclose axial fit in said groove, and cotters.

9. The combination dened in claim 1 in which said wider end of saidfrusto-conical shell is rigidly connected to the axially outer portionof said partition.

10. The combination defined in claim 1 in which said means forconnecting axially fast and for centering nonrotatably said outlet-sideend` of said supporting ring relatively to said inner housing comprise aradial groove in one of said two parts and a corresponding radial key inthe other of said two parts, said key engaging with close axial fit insaid groove, and cotters.

11. The combination defined in claim 1 in which said outer housing, theportions of said inner housing lying on the inlet-side and on theoutlet-side of said guide apparatus, the radially outer portion of saidpartition, and said supporting element are diametrically split.

12. The combination defined in claim 1 in which said guide apparatus isdiametrically split.

13. The combination defined in claim 1, in which said guide apparatuscomprises a plurality of axially spaced diametrically split two-partguide-blade rings each receiving one of said circular series of guideblades, a plurality of one-part intermediate rings, arranged so as toalternate contiguously with said guide-blade rings, and means forcentering and for non-rotatably connecting said rings relatively to eachother.

14. The combination defined in claim 13 in which one of two immediatelyadjacent rings has, on its end face facing the other ring, a rim, andthe other ring has, on its end face facing the former ring, acorresponding recess, said rim engaging with close fit Iin said recess,so as to center said adjacent rin-gs relatively to each other.

15. The combination defined in claim 13 in which said means fornon-rotatably connecting said rings relatively to each other compriseaxially extending screws and cotters.

16. In an axial fiow gas or steam turbine, a diametrically splittwo-part outer housing and an inner housing, said housings confining anintermediate space; heat insulating material disposed in saidintermediate space, said inner housing comprising a diametrically splittwo-part inletportion, a guide apparatus portion and a diametricallysplit two-part outlet-portion; said guide apparatus portion comprising aplurality of axially spaced .diametrically split two-part guide-bladerings each having a circular series of inwardly extending guide blades;a plurality of one-part intermediate rings, arranged so as to alternatecontiguously with said guide-blade rings; said rings thus forming astationary guide apparatus; said intermediate rings having on their endfaces an inner rim, and said guide-blade rings having on their end facesfacing one of said intermediate rings a corresponding recess, each ofsaid rims engaging with close fit in the corresponding recess so as tocenter said guide-blade rings and said intermediate rings relatively toeach other; each of said guide-blade rings having an outer peripheralgroove; each of said intermediate rings being connected axially fast andnon-rotatably to each other to the two immediately adjacent guide-bladerings by a circular series of axial screwbolts passing through theintermediate ring and extending into said outer peripheral :grooves ofthe guideblade rings, the nuts of the screwbolts lying in said grooves,and by cotters; a partition separating said intermediate space in aninlet-side intermediate space and in an outlet-side lintermediate space;said partition comprising a diametrically split two-part ring, inwardlyextending lugs fixed at said ring having at their inner ends cotters forcentering deplaceably in axial direction the outletside end of saidguide apparatus, a sealing ring comprising a one-part outer ring mountedaxially fast in a sealing manner in said outer housing and a one-partinner ring co-axial with said outer ring and mounted rigidly in asealing manner on said outlet-side end of said guide apparatus, so as toconnect said partition in a sealing manner with said outlet-side end ofsaid guide apparatus, and a thin corrugated one-part daiphragm bridgingthe coaxial play between said two rings of said sealing ring; an innerperipheral groove in said outer housing in which the radially outer partof said two-part ring of said partition and the radially outer part ofsaid one-part outer ring of said sealing ring engage, the former axiallyadjacent at the inlet-side end face of the other, with close axial fitin said inner peripheral groove of said outer housing, thus connectingsaid two-part ring of said partition and said one-part outer ring ofsaid sealing ring axially fast in a sealing manner with said outerhousing, and cotters for centering non-rotatably said two-part ring ofsaid partition relatively to said outer housing; a supporting elementfor supporting said inner housing, having a frusto-conical thin-walledshell consisting of material of low thermal conductivity, its Wallhaving openings, arranged in said inlet-side intermediate space,co-ax-ial with said guide apparatus, its Wider end rigidly connected tosaid two-part ring of said partition so as to be connected axially fastand centered non-rotatably relatively to said outer housing, acylindrical supporting ring, having longitudinal slots, its wall partsbetween said longitudinal slots in the peripheral direction amounting toa multiple of the wall thickness, co-axial with said guide apparatus,and surrounding the latter over its outlet-side part, the narrow end ofsaid frusto-conical shell being rigidly connected to the inlet-side endof said supporting ring, a two-part con- 7 8 nection ring being rigidlyconnected tothe outlet-side end cotters for centering non-rotatably saidends of said parts of said supporting ring and at the saine time axiallyand relatively to each other. radially neighbouring the outlet-side lastof said guidey blade rings, said connection ring thus forming saidoutlet- References Cited by he'EXaIIlillel' side end of said guideapparatus, said outlet-side last of 5 UNITED STATES PATENTS said guideblade rings having an outer radial key, and said 2,445,661 ,H1948Constant et al.

connection ring having an inner radial groove, said key engaging withclose axial t in said groove, so as to con- MARTIN P SCHWADRON prima]Examiner nect axially fast said outlet-side end of said supporting v yring to said outlet-side end of said guide apparatus, and 10 E. A.POWELL, JR., Assistant Examiner-

1. IN AN AXIAL FLOW GAS OR STEAM TURBINE, AN OUTER HOUSING AND AN INNERHOUSING, SAID HOUSINGS CONFINING AN INTERMEDIATE SPACE; HEAT INSULATINGMATERIAL DISPOSED IN SAID INTERMEDIATE SPACE; A PLURALITY OF AXIALLYSPACED CIRCULAR SERIES OF INWARDLY EXTENDING GUIDE BLADES ARRANGED OVERAN AXIAL PORTION OF SAID INNER HOUSING; SAID AXIAL PORTION OF SAID INNERHOUSING AND SAID GUIDE BLADES THUS FORMING A STATIONARY GUIDE APPARATUS;A PARTITION SEPARATING SAID INTERMEDIATE SPACE INTO AN INLET-SIDEINTERMEDIATE SPACE AND AN OUTLET-SIDE INTERMEDIATE SPACE; MEANS FORCONNECTING AXIALLY FAST IN A SEALING MANNER AND FOR CENTERING SAIDPARTITION NON-ROTATABLY RELATIVELY TO SAID OUTER HOUSING; MEANS FORCENTERING AND FOR CONNECTING IN A SEALING MANNER SAID INNER HOUSING TOSAID PARTITION TO BE AXIALLY DISPLACEABLE RELATIVELY TO THE LATTER; ASUPPORTING ELEMENT FOR SUPPORTING SAID INNER HOUSING, HAVING ATHIN-WALLED FRUSTO-CONICAL SHELL CONSISTING OF MATERIAL OF LOW THERMALCONDUCTIVITY, ARRANGED IN SAID INLET-SIDE INTERMEDIATE SPACE, CO-AXIALWITH SAID INNER HOUSING, ITS WIDER END FACING SAID PARTITION, AND MEANSFOR CONNECTING AXIALLY FAST AND FOR CENTERING NON-ROTATABLY SAID WIDEREND OF SAID FRUSTO-CONICAL SHELL RELATIVELY TO SAID OUTER HOUSING, AND ASUBSTANTIALLY CYLINDRICAL SUPPORTING THE LATTER AT LEAST SAID INNERHOUSING AND SURROUNDING THE LATTER AT LEAST OVER PART OF SAID GUIDEAPPARATUS, THE INLET-SIDE END OF SAID SUPPORTING RING BEING RIGIDLYCONNECTED TO THE NARROWER END OF SAID FRUSTO-CONICAL SHELL, AND MEANSFOR CONNECTING AXIALLY FAST AND FOR CENTERING NON-ROTATABLY THEOUTLET-SIDE END OF SAID SUPPORTING RING RELATIVELY TO SAID INNERHOUSING; AND OPENING IN THE PORTION OF THE WALLS OF SAID SUPPORTINGELEMENT LYING WITHIN SAID INLET-SIDE INTERMEDIATE SPACE.